Welcome Guest - Sign Up today
Welcome Guest - Sign Up today
Store Links Mobile - Shop Now



Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
See more
See less

Another erratic tach, '97 Johnson SPL

  • Filter
  • Time
  • Show
Clear All
new posts

  • Another erratic tach, '97 Johnson SPL

    I am trying to get a tach working on a new to me J90TSLEU. It has an unregulated charging system. I took a tach I had from a '89 Evinrude 40 hp and tried to use it. It had been acting erratically on the 40, usually reading way high randomly, then going back to normal. It did pretty much the same thing on the 90 so I figured it was bad. I bought a new Teleflex Amega model 58255P. The application chart says it will work with "Evinrude / Johnson, All V Models" At the bottom of the chart it says "Johnson / Evinrude 88 - 112 SPL models may require the addition of a 2000 ohm resistor or a BRP regulator." The installation instructions do not mention this resistor or where to install it. I called Teleflex tech support, and was told to place it inline with the signal wire, then the tech called me back and said he made a mistake and to put it inline with the ignition (purple) wire. I did this and the tach did not work at all, not even go to zero when swithced on. The voltage after the resistor was about 2.8. I removed the resistor and the tach seemed to work OK on muffs at idle and high idle. On the water, idle and at no wake speed it seemed OK. When I opened it up, tach climbed up and at what I guess was 4000 - 4500 rpm it dropped down to read 1200 or so, when I backed down to cruise speed, guessing 3500 - 4000 rpm, the tach climbed up to full scale, 7000. It did this several times. I reinstalled the resistor in the ign. wire and the tach does not work at all.

    Searched other erratic tach posts here and they usually point to rectifier problems. My rectifier checks out good with ohmmeter test per service manual. I did not try to heat the rectifier to see if results change. All connections and wiring are good.

    Does anyone know where to connect the 2k ohm resistor, if in fact it is required? The tach instructions say it "may" be required. Or do I need a regulator? If so, do I replace my rectifier with the BRP rectifier/regulator from the higher output stators, or is a seperate regulator available as an add-on?

    Any other tricks to install tach on SPL engines before I call Teleflex again?

    Oh, the selector on the tach is set to 6 per service manual and tach instructions.

    I'm trying to figure out what prop pitch I need for this boat/ engine, plus I just like having a tach I can trust.

    Thanks guys.

  • #2
    Re: Another erratic tach, '97 Johnson SPL

    The resistor is suppose to be installed between the send terminal (gray wire) and gound. Seems like Teleflex should know that.
    "A manual is a cheap investment"
    Fair Winds and Following Seas
    PTC USN ret


    • #3
      Re: Another erratic tach, '97 Johnson SPL

      Thanks, bhile. I'll do that tonight. Unfortunately, can't on-water test til the weekend. I'll reply with results.


      • #4
        Re: Another erratic tach, '97 Johnson SPL

        I have the same results with the resistor installed between the signal and ground posts. Seems OK up to about 3500, then goes crazy, full scale, low reading, floating around, etc. What else should I check? Do I need a voltage regulator for accurate tach readings? Or a OMC/BRP tach designed specifically for these SPL motors? Maybe new tach is bad out of the box?

        Thanks for any suggestions.


        • #5
          Re: Another erratic tach, '97 Johnson SPL

          Ooops! Ignore my last post about same results with resistor between send and ground. I had it in line with send wire. I'll try again, results next weekend unless I can sneak away early from work during the week. BTW I saw an old post about an erratic tach which suggested the resistor between the ign and ground posts. Is this an either / or situation?


          • #6
            Sign up today
            Re: Another erratic tach, '97 Johnson SPL

            Thanks, bhile. The resistor between the send and ground terminals did the trick, tach is smooth and steady now. Teleflex should print this simple solution in the installation instructions!